Sec. 4. MASTER PLAN. The county engineer shall, when funds are available and when authorized by the commissioners court, to do so, make a careful and thorough study of all roads at that time opened and constructed with a view of determining what new roads and connections of roads should be opened and constructed, as well as what roads should be widened and improved. In making such survey, he should take into consideration the convenience of the traveling public, and especially the convenience of the citizenship of the county, so that each community a part of the county shall have easy and practical connection with the other and the state highway system of roads in the county, thereby furnishing to the citizenship of the county a convenient means of ingress and egress into and out of every city and town, as well as every other community in the county. The roads indicated in such surveys to be opened and constructed, as well as existing roads that are designated to be widened and improved, shall be located and designated with the view of giving the entire county an efficient road system. The commissioners court shall, in selecting roads or new roads, as well as the improvement of existing roads, look to the density of the population and amount of traffic that will normally flow over such roads; such survey when completed by the engineer, and when adopted by the commissioners court at a regular meeting thereof, shall be known as the Master Plan. When such Master Plan has been completed and adopted by the court as it is stipulated, the same shall be made into permanent record form and kept by the county engineer, and after such adoption, all new construction, widening and permanent improvement shall be done in accordance with such Master Plan and with the view of ultimately completing the same, both as to location and character of construction. The construction of said Master Plan shall proceed as the available funds of the county will permit, and each unit of such construction shall be made in accordance with such Master Plan. The order in which the roads or projects in the construction of said Master Plan are constructed shall be determined by the county engineer, with the approval of the commissioners court and in determining the priority of roads or projects, the engineer and court shall take into consideration the necessity and convenience of the public and should give priority to those roads or projects that will result in the greatest service to the greatest number of the citizenship of the county, looking at all times to the entire county as a unit and wholly disregarding precinct lines.

Sec. 5. ADOPTION AND AMENDMENT OF MASTER PLAN. The commissioners court shall when said Master Plan is submitted to them for adoption, or if after adoption, an amendment or change thereto shall be deemed advisable, set a date at a regular meeting of commissioners court called for that purpose, and give public notice thereof at least two weeks in advance of such meeting and the purpose thereof, inviting the citizenship of the county to be present to protest any part of said Master Plan and also to make such suggestions as they deem pertinent in connection with same, or any change therein, but the decision of the commissioners court shall become and be final and conclusive as to said Master Plan, and no succeeding commissioners court shall have the power or authority to alter or change or amend any of the provisions thereof except by unanimous vote of the commissioners court. Provided, that where such Master Plan has once been adopted, there shall be no necessity to repeat the same in absence of public necessity thereof, for same may be amended and altered when public necessity therefor is shown, and after notice is given as herein above provided.

Sec. 6. SUBDIVISIONS. It shall be the duty of the county engineer and the commissioners court in each respective precinct to cause the Master Plan to be conformed to the needs and demands of existing and new subdivisions by constructing adequate highways leading from such subdivisions to the county seat. Provided that from and after the passage of this Act, the commissioners court, before approving the plan or plans of any subdivision lying outside the corporate limits of any city, town, or village, as required by Article 6626, Revised Civil Statutes of Texas, 1925, as amended, shall require such subdivision to enter into a written contract in agreement with the county, then such subdivider or dirt dealer will grade, and gravel all streets and provide all necessary drainage structures within such tract of land so subdivided. Such street improvements and drainage structures shall be in accordance with standard plans and specifications prepared by the county engineer. Such contracts shall be for the benefit of any person or persons, firm or corporation who may thereafter acquire by purchase or otherwise any lot or lots in said addition or subdivision, and the faithful performance of said contract as to the initial improvements of said streets shall be deemed a part of the consideration paid for said lot and be read into the contract of sale of same, and such contract shall be enforceable at the instance, if necessary, of the owner or owners of any lot or lots in a given subdivision, suing singularly or as a group or class. After such initial street improvements have been completed in accordance with such plans, said streets then become and remain a part of the county road system and shall be maintained by the county unless and until included within the corporate limits of a city, town or village capable of maintaining its own streets.